To make a fake fingerprint, you will first need a real fingerprint. For a first try, start for example by pressing your finger in a piece of putty. Latent fingerprints or invisible fingerprints can also be used to make false fingerprints, but this will require much more time and equipment.
Steps
Method 1 of 2: Use putty and gelatin
Step 1. Make an impression in a material the consistency of putty
Putty, play dough or clay will be good options, as long as the material is new and clean. Roll a small piece of the chosen material into a ball and press the finger whose imprint you want to imitate into the ball.
A hot, flat piece of paraffin will give you even better results, but you will need to press your finger on it for 5 to 10 minutes
Step 2. Refrigerate the putty
By placing the material in the freezer or refrigerator, you will keep the imprint as hard as possible while you work it. Different materials and different brands of product will not all react to cold the same way. Some can then no longer be used as putty, which does not matter what you are going to do with them here.
Step 3. Prepare a very thick gelatin
Boil water in a small saucepan, then add the same amount of gelatin. Stir constantly for several minutes, so as to dissolve the powder as best as possible. Let the preparation cool.
Step 4. Microwave the gelatin
Once the gelatin has cooled and forms a thick gel, melt it in the microwave, then let it freeze again. Repeat the operation until the material no longer contains any bubbles. Take a small drop: the preparation should be thick and rubbery.
Step 5. Pour the gelatin into the fingerprint mold
Once the gelatin is chewy and bubble free, melt it one last time. Pour the hot, liquid gelatin into the fingerprint mold you made in the putty.
Step 6. Place everything in the freezer
Place the gelatin and mastic in the freezer. Within minutes, the gelatin will harden and form a solid, rubbery substance. Carefully loosen the gelatin from the mastic. You now have a fake fingerprint, with the reliefs of a real fingerprint on the surface of the material.
Method 2 of 2: Use advanced techniques
Step 1. Read the instructions carefully before you start
This method will allow you to obtain a much more precise impression. You won't need to use putty, but you will need much more specialized equipment. Only try this method if you have access to these tools. You will need a high quality scanner or a good camera and a circuit board. A projector transparency can be used instead of the circuit board, but the operation will be less efficient.
Step 2. Look for fingerprints
This method will allow you to create a fake print from a real fingerprint left on a touchscreen, doorknob, or other dry, shiny surface. To spot these fingerprints, you can sprinkle a surface with a crushed powdered graphite pencil lead or with black powder from a fingerprinting kit.
This method will work best on a white surface
Step 3. Take a good quality scan or photo
For best results, photograph or scan the imprint with a resolution of at least 2400 dpi. Load the captured image on your computer and open it in photo editing software.
Step 4. Reverse the direction and colors of the image
Using the software, flip the image from left to right, in order to obtain a mirror image. Also invert the colors of the image, so that the reliefs of the imprint are white and the background of the image is black.
Step 5. Transfer the image to the circuit board or transparency
For best result, print your impression on tracing paper, then use a UV engraver to transfer the impression to the circuit board. If you don't have tracing paper, you can simply print the imprint directly onto the transparency, although this will be less efficient.
Step 6. Make the false impression with graphite and wood glue
The image of the imprint on the printed circuit or on the transparency will be slightly raised and you can use it to make a false impression. To do this, cover the image with graphite powder, then cover it with a thin layer of white wood glue or light-colored latex milk.
By adding a small dose of glycerin in the wood glue, it will be slightly more liquid and easier to work, which will make the material more effective
Step 7. Remove the dry glue impression
Once the wood glue has dried, carefully peel it off the surface and inspect your footprint. You can even cut out the material around the imprint, then use special effects glue to stick it on your finger.
